Identifying corner slide window Parts

Question

This part is on top side of the slide window, but I have no idea what the name is. It came off when I opened one. Help would greatly appreciated.

User submitted photos of window hardware.

Tom · Accepted Answer

The part you're looking for is known as a "top sash guide." Yours in particular resembles our 18-124P, for the right and left side, respectively. I recommend removing an undamaged top sash guide from the window to confirm that these are a match.